Process of producing molybdenum containing alloys



Patented July '21, 1942 PRDCESS OF PRODUCING MOLYBDENUM CONTAINING ALLOYS Arthur Linz, New York, N. Y., assignor to Climax Molybdenum Company, New York, poration of Delaware N. Y., a cor- No Drawing. Application August 13, 1940, Serial No. 352,415

4 Claims.

The present invention relates to the new and useful process-for the addition of'molybdenumsilicon compounds to ferrous metals.

Objects and advantages of th'e' lnvention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practies with the invention, the same being realized of which require special care to produce dhUlllO-f geneous resulting alloy. It has also been pro posed to add molybdenum and silicon to molten iron or steel by using a mixture of molybdenum trloxide and silicon, but this process has'not come into commercial use due to the nature of the reaction which takes place at the temperature of the molteniron or steel, and also because it disperses the slag which it forms causing inclusions of silica slag.

The present invention has for its object the provision of a novel and improved process for the addition of molybdenum-silicon compounds to molten iron or steel. By this process the solution of the added ingredients is made more rapid than heretofore, a more homogeneous alloy results, and the slag inclusions are avoided. I'he invention also provides a single compound which introduces a useful ratio of molybdenum and silicon into the molten metal, such as iron or steel, and giving the added commercial advantage that foundry practice can be simplified. Furthermore, this'invention provides for the addition of molybdenum-silicon compounds which react exothermically at the temperature of the molten metal, rather than absorbing heat from the metal which is disadvantageous in practice. The invention also has for its object the provision of a simple, effective and relatively inexpensive process for the addition of predetermined relative amounts of molybdenum and silicon to molten metals.

In general, the process of the present invention comprises adding a molybdenum silicide, with or without an excess of silicon, to the molten'metal, and this addition may be made to the molten improve to use the molybdenum silicide MOSi2, other molybdenum silicides may be used, such as M02813, and the like (Honigschmid, Karbide and Silizide; Wedekind and Pintsch, German Patent No. 294,267; Felder-Clement A. 0., German Patent No. 359,785; Watts, Bull, University of Wisconsin #145, pp. 294, 295 (1906)).

While various processes may be used for the preparation of the molybdenum-silicon addition agent, which may be used in the alloying process of the present invention, I preferably mix a molybdenum oxide, such asroasted molybdenite concentrates or pure molybdenum trioxide with ferro-silicon, aluminium and some flexing agent, such as fluorspar. The mixture is then ignited in a suitable crucible, and after the slag has been tapped off, there remains a complex molybdenum silicide containing the desired proportion of molybdenum and silicon, together with a small amount of iron which is probably present as a ferro-molybdenum-silicon complex.

The relative amounts of these substances may be varied widely, dependent upon the desired composition of the resulting product, but as a typical example I may use the following:

Kilograms Molybdenum in roasted molybdenite concentrates 100 Ferrosilicon (75%) 60 Aluminium Fluorspar 15 A typical analysis of the product of the reaction of such a mixture is:

Percent Mo 5'7. Si 30.00 Al 21 S102 2. 54 CaO 3. 60 A: 6. 98

metal in the ladle, or elsewhere, while I prefer 55 be crushed to form smaller lumps oi the alloying material which can be weighed out. into convenient amounts for addition to the moltenmetal.

In use, the molybdenum silicides are used in substantially the same manner as is customary with i'erro-alloys, and the alloying material is added directly to the moltenhmaterial, as for instance, in the ladle, although the molybdenum silicide has a diflerent range of useiulness than the ferro-molybdenum due to its exothermic nature and by reason'o! the fact that the simultoneous addition of both molybdenum and silicon is accomplished. These properties combine to make the process of the present invention superior and insure the production of an alloy with superior physical properties than is frequently the case with ferro-molybdenum.

If desired, the molybdenum containing ferrous alloy may be produced in a blast furnace or electric furnace, by mixing the molybdenum silicide in a proper quantity with the ferrous material charged to the iumace, and in this case the molybdenum silicide is dissolved in the ferrous material as the ferrous material is melted.

Alternatively, the molybdenum silicide may be used to replace a portion of the now commonly used ferromolybdenum, in case a smaller proportion of silicon is desired in the final alloy, and similarly, molybdenum silicide may be used in combination with silicon addition agents, such as ferrosilicon, calcium silicide, etc., if a larger proportion of silicon is desired in the final alloy.

While the process has been described principally in connection with the production of ferrous alloys having a molybdenum and silicon content, the process may also be applied to the production of non-ferrous alloys, such as aluminum and magnesium alloys.

The invention in its broader aspects is not limited to the specific steps and procedures described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

1. The process of producing molybdenum containing alloys which comprises mixing a molybdenum silicide with material to be alloyed and dissolving the molybdenum silicide in the metallic material at a temperature sufllcient to melt the metallic material.

2. The process of producing molybdenum containing alloys which comprises adding a molybdenum silicide to molten metallic material.

3. The process of producing molybdenum containing alloys which comprises adding a molybdenum silicide to metallic material and melting the metallic material to dissolve and absorb the molybdenum silicide.

4. The process of producing molybdenum containing alloys which comprises mixing a molybdenum silicide with a metallic material at a temperature sufficient to dissolve the molybdenum silicide in the metallic material.

ARTHUR LINZ. 

